Friday, February 2, 2018

Evolang one more time

Footnotes to Plato is a blog run by a philosopher-biologist named Massimo Pigliucci (MP). It has lots of interesting material and I have personally learned a lot by reading it. Currently, MP is writing a multi part commentary on a new book on evolution Darwin’s Unfinished Symphony by Kevin Laland. It’s on the evolution of culture and its impact on the evolution of mind. It is actually a pretty good read and, unlike much of the literature that discusses mind and culture, it does not fall into the continuity thesis trap that takes what humans do to simply be a beefed up version of what other animals do. In other words, it rightly treats the human case as different in kind and asks how this difference might have arisen. I don’t agree with everything Laland proposes, but it starts with the right presuppositions (what humans have really is different) and proceeds from there (see here for some brief discussion).

MP’s latest installment of his running commentary on Laland’s book (here) addresses the evolution of language. In the chapter, Laland surveys traditional accounts for how language arose in the species. Here is the list that MP compiled:

  • To facilitate cooperative hunting.
  • As a costly ornament allowing females to assess male quality.
  • As a substitute for the grooming exhibited by other primate species.
  • To promote pair bonding.
  • To aid mother-child communication.
  • To gossip about others.
  • To expedite tool making.
  • As a tool for thought.
Laland finds these wanting and adds another contender: language evolved to teach relatives. Laland spends lots of time in previous parts of his book arguing that learning via imitation and observation is a key feature of biological minds and that this power promotes biological success of the evo relevant variety. In this context, it is pretty clear why the pedagogical role of language might find a spotlight: language looks like an excellent medium for molding minds (though parents and teachers might beg to differ regarding how efficient a method it is!). At any rate, Laland’s proposal is that language evolved for instructional purposes, rather than to make tool making easier, or gossip more salacious, or promote pair-bonding or, or, or… Of course, once language arrived on the evo scene it could have served all these other functions as well, but according to Laland that was not what set the whole language thing in motion. Nope, it arose so that one day we could have long and boring faculty meetings at pedagogical institutions like UMD.

MP’s post critically reviews Laland’s proposal and points out that it does not obviously do better on the criteria proposed than do variants of the other rejected approaches. Moreover, MP argues, all these evo scenarios share a common difficulty; because the evolution of language has happened exactly once (i.e. it is a unique evo event) it’s very hard to provide convincing evolutionary evidence of the sort typically on offer for the various alternative scenarios. Here is MP:

For me, though, what makes this chapter the least convincing of those we have read so far is that even if we grant Kevin everything he is arguing for, we are still left, at best, with an hypothetical scenario that falls far short of empirical verification. Yes, maybe language evolved so that we could efficiently teach valuable information to our relatives, and things then went on from there. Or maybe there is a clever variant of one of the other hypotheses now on the table that will be even more convincing than the present analysis. Or perhaps there is yet another scenario that simply nobody has thought up yet. We just don’t know. And to be honest I don’t think we are likely to know any time soon, if ever. Precisely because of a major stumbling block acknowledged by Laland himself: the evolution of language was a unique historical event, and unique historical events are exceedingly difficult (though not impossible) to study.

MP goes on to flag Lewontin’s skepticism regarding the availability of robust evolutionary accounts for cognitive traits given the paucity of footprints in the fossil record left by the exercise of such capacities (see here). Lewontin’s point, that MP endorses, is that it is unlikely that we will ever get enough evidence to build a compelling case for the evolution of any human cognitive trait, including (especially!) language given its biological uniqueness and the faint traces it physically leaves.

I agree with much of this, but I think that it misses the real problem with Laland’s discussion, and with the other scenarios MP catalogues. The big hole in these accounts is that they fail to specify what exactly language is. In other words, the projects fail from the start as they do not sufficiently specify the cognitive capacity whose evolution we are interested in explaining.[1] What exactly is it that has evolved? What are its key properties/characteristics? Only after specifying these does it make sense to ask how it and they arose. Sadly Laland doesn’t do this. Rather he seems to presuppose that we all know what language is and so specifying the relevant capacity of interest in some detail is unnecessary. But linguists know that this is wrong. Language is not a simple thing, but a very complex capacity and so asking how it evolved is asking how all of these complex intricacies came together in humans and only in humans. So, the real problem with Laland (and MP’s discussion) is not just that relevant data bearing on evolutionary scenarios sucks (though it does) but that most of the discussions out there fail to specify what needs explaining. Only after answering this question in some detail can the evolutionary question even be broached coherently.

Let me expand on this a bit. MP starts his comment on Laland as follows:

Despite much talk of animal communication, that’s just what other species do: communicate. Language is a very special, and highly sophisticated, type of communication. Characterized by grammar, capable of recursivity, inherently open ended. Nothing like that exists anywhere else in the animal world. Why?

Given this preamble, the thing that MP (and I assume Laland) thinks needs explaining is how a certain kind of grammar based system of communication arose, with emphasis on ‘grammar’ (after all, this is one key factor that makes human communicative systems unique).

So what features does such a system have? Well, it generates unboundedly many hierarchical structured objects that pair a meaning with an articulation. But this is not all. In addition, its use is very very labile (there is no apparent restriction on the kinds of topics it can be used to “discuss” and it exploits a lexicon several orders of magnitude larger than anything else we find in animal communication systems and whose entries have semantic features quite unlike those we find with other animals. In sum, the syntax of human language, the vocab of human language and the applicability of human language are each unique.

More specifically, as GGers know human Gs embody a very specific form of hierarchical structure (e.g. binary branching, labeled nodes), a very specific form of recursion (e.g. Merge like rather than say FSG like) and human G use is open ended in many different ways (e.g. its use is not stimulus bound (i.e. you can talk about what’s not right before your eyes (viz. independently of the famous 4-Fs) or even actual), the semantics of its atoms are not referentially constricted,[2] its domain of application seems to be topic neutral (i.e. not domain restricted like, say, bee dances or vervet alarm calls)). And all of the above is still a pretty surfacy description of just some of distinctive features of human language (there is nothing quite like morphology evident in other communication systems either). As any GGer can attest, the descriptions available for each of these features that are empirically well motivated are endless.

I could go on, but, even this very cursory and brief description suffices for the main point I want to make: if these are the features that make human language unique then the evolutionary forces Laland lists, including his own, don’t in any obvious way get anywhere near explaining any of them. To wit: How does the fact that language is used to teach realtives or to gossip about them (or others) explain the fact that human Gs are hierarchically recursive, let alone recursive in the specific way that they are? How does the possibility that language promotes pair bounding or can be used to identify predators or to support good ways to hunt explain why human linguistic atoms are not particularly referentially bound? How does the claim that language can guide tool making or teach migration patterns explain why humans can use language in a non-stimulus bound way? How do any of these “functions” explain why the domains of application of human language are so labile? They don’t. Not even close. And that is the real problem. Not only is relevant evidence hard to come by (i.e. Lewontin’s point) but, more importantly, the form of the accounts are conceptually insufficient to explain the (acknowledged) unique features of interest. The problem, in other words, is that the proposals Laland (and MP) survey fail to make contact with the properties that need explaining. And that is far more problematic than simply being empirically hard (maybe, impossible) to verify.

Let me be a little harsher. A standard objection (again from stemming from Lewontin) is that many evolutionary accounts are just-so stories. And this is correct. Many are. And this is indeed a failing. Let’s even say that it is a very serious failing. But whatever their vices, just-so stories do have one vital ingredient missing from the accounts Laland and MP survey: were they accurate they would explain the relevant feature. Why did moths go from light colored to dark when pollution arose? Because the white ones were less able to camouflage themselves and were eaten leaving only the dark ones around. I don’t care if this story is entirely correct (but see here reporting that it is). It has the right form (i.e. if correct it would explain why the moths are speckled dark). So too stories we tell about why polar bears are white and why giraffe necks are long. However, this is precisely what is missing from most EvoLang accounts, including Laland’s. Or more precisely, if the features of interest are the ones that MP notes at the outset (which, recall, MP flags as being what makes human communication systems distinctive), then it is entirely unclear how the gossiping, teaching, cooperating would fuel the emergence of a system that is recursive, non-referential, domain general and stimulus free. So, the accounts fail conceptually, not just empirically. These accounts are not even just-so adequate. And that is a big failure. A very big failure. Indeed, an irreparable one![3]

I could go further (and so I will). Given an FL like ours which produces Gs like ours with generative procedures like ours and vocabulary items like ours it is pretty easy to tell a story as to how such a system could be used to do wonderful things, among others teach, gossip, makes tools, coordinate hunts, discuss movie reviews and more and more and more. That direction is easy. Given the characteristics of the system of language the variable uses it can be deployed in service of is pretty easy to understand. Not so the opposite. Even if teaching or bonding or gossiping is important it is not clear why doing any of these things demands a system with the special properties we find. One could imagine a perfectly serviceable teaching system that did not exploit lexical items with the peculiar semantic properties ours do or did not have generative procedures that allowed for the construction of endlessly hierarchically complex structures or that allowed for vastly different kinds of articulators (hands and tongues) or… You get the point, though, sadly, it seems to be a hard one to get. It is the point that Chomsky has been repeatedly making for quite a while now and it correctly flags the fact that an adequate evolutionary account of a capacity logically require a specification of the capacity whose evolution is being accounted for. This, after all, is the explanadum in any EvoLang account and, as such, is the explanatory target of any admissible explanans. Laland doesn’t spend much time specifying the features that make human language unique (the one’s that MP limns) and so spends no time explaining how his candidate proposal leads to communicative systems with these properties. Not surprisingly, then, the accounts he surveys and the one he provides don’t explain how these capacities could have arisen, let along how they actually did.

So, another discussion of evolang that really gets nowhere. This is nothing new, but it is sad that such smart people (and they are very very smart) are derailed in the same old uninteresting way. We really do know a lot about human language and its unique features. It would be nice if evolutionary types interested in evolang would pay some attention (though I am really not holding my breath).

[1] The very first comment on MP’s post by saphsin correctly makes this point.
[2] See here for some discussion of this and more specifically Paul Pietroski’s discussions of how little linguistic meaning has to do with truth (e.g. Paul’s contribution here and articles on his webpage here).
[3] I do know of a story that does not make this mistake and that concentrates on trying to explain some features on evolutionary terms. It’s one that Bob Brandon and I provided many many years ago here: From Icon to Symbol:  Some Speculations on the Evolution of Natural Language (1986), Philososphy & Biology. Vol. 1.2 pp.169-189. This speculative paper no doubt suffers from Lewontin’s critique, but at least it tries to isolate different features of the overall capacity and say which ones might be have an available evolutionary explanation. This virtue is entirely due to Robert Brandon’s efforts (he is a hot shot philosopher of biology and a friend).


  1. Laland's `instructional' view sounds very like Daniel Cloud's (though Cloud adds a `domestification' dimension), which I wrote a critique of in the Times Literary Supplement in 2015 (